In this tutorial I'll discuss two methods used in "Emelia" for
making long hair for the characters. The first is based on guide curves that determine
the basic shape and flow of the haircut. Paint Effects hair is then interpolated
between the guide curves. It sounds complicated, but really it's pretty simple.
I'll walk you through the basics here.
First you'll need to create nurbs geometry to represent the hair. This geometry
will allow you to see interactively how your hairdo is coming along so you can
design the look before you get into the Paint Effects stuff. In the example of
the mom here to your left, I designed the hairdo in various hair "clumps" each
made from separate lofted nurbs surfaces. For a different type of hair cut like
Jimmy here below on your right, his hair consisted of two nurbs surfaces, one
on each side of the part in his hair.
It's very important that the isoparameters
(shown here in red) of your geometry really flow in the direction the hair would
go, as you can see on the comparison of Jimmy with "correct" hair direction on
his isoparameters and "wack" hair direction (unless you're going for a comb-your-hair-into-your-face
look I suppose). This can take some getting used to if you are not used to modeling
this way.
When you've got your hair geometry looking like you want, you are ready to create
the guide hair curves for your Paint Effects hair. Select the isoparameter at
the base of your nurbs surface where the hair will grow out of (shown here in
blue), and then the perpendicular isoparameters that flow in the direction of
the hair (shown in red). Use "offset curve" to convert all these isoparameters
into curves.
Once you have your curves, you can then further edit their
CVs to add detail. For instance with Jimmy I moved the guide curves around to
make his hair a bit more unkempt as you can see bellow on the left.
The next step is to take a Paint Effects hair brush and attach it to
the "scalp curve" (illustrated in blue) using "attach brush to curves". This is
where your hair will grow out of. Once you've done that you then assign all the
guide curves (illustrated in red) to the brush using "set stroke control curves".
Both of these commands are under the "curve utilities menu" in the main
Paint Effects menu.
You'll need to adjust some parameters in the Paint Effects attribute editor still,
the most important being setting "curve flow" to "1". You can find that
in the "tubes | Behavior | forces" section of your Paint Effects brush.
Now you should have Paint Effects hair flowing out from the base "scalp curve"(blue)
and along your "guide curves"(red). On the right you can see the resulting Paint
Effects strokes for a single "clump" of Mom's hair. Another thing I modified was
the width of the tubes: Because I was going for a cartoon look I set the width
to be pretty thick so instead of drawing each hair, it drew "fat hairs" mimicking
the way hair kind of bunches together (you can see how this looks rendered at
the top of the page).
That's pretty much all there is to it. In summary:
Start with a stand-in geometry of your hair, convert its isoparameters into curves,
then use those curves to guide your Paint Effects hair. You can use this basic
method to come up with all sorts of hair styles. For a more in depth look at the
settings in Paint Effects that you will need to know about for making human haircuts
(Paint Effects has a bazillion attributes which can be daunting), take a look
at this great tutorial by
Yinako
Continue on below to read about how I combined this method
with a fake-fur shader I wrote to make the hair for the main character in the
film for the main characterEmelia.
